Automatically adjustable c clamp



w. J. MALECKI AUTOMATICALLY ADJUSTABLE c CLAMP July 7, 1953 2 Sheets-Sheet 1 Filed Feb. 19,1949

w. 2 5 m y 4 A .b KC 5 S 4??? MN m 1 N I. /I.W 1T N f M A n In w Patented July 7. 1953 UNITED STATES PATENTFOFFICE Application February 19, 1949, Serial No. 77,329

3 Claims.

, The present invention relates to new and useful improvements in clamps.

More particularly, the present invention proposes a novel quick-release screw-clamp, and the aim is to provide a novel and valuable such clamp and one of outstanding utility when in the form of a so-called C-clamp and hence illustrated herein in connection with a C-clamp; the present invention being characterized by a marked simplicity of construction and ruggedness throughout, thereby to give a dependably long life, and at the same time characterized by a superior means for manual actuation instantaneously to free the screw from meshing'relation of its thread with the thread of a nut.

A further feature of the invention is that while a spring means, one which preferably is a onepiece single unit, is employed, for normally holding the screw to said meshing relation, merely a single simple manual thrust is required to overcome the pressure of the spring means and thereby temporarily throw the nut thread out of engagement with the screw thread, that is, merely a single manipulable part has to be handled, by depressing the same, toeffect this break-of-engagement result.

Another feature of the invention is the provision of .a combination of parts such that when said manipulable part is depressed, the two jaws of the clamp thereby are wholly freed for straight endwise and parallel movement toward and away from each other, Without impediment of any kind.

Another object of the present invention proposes a'novel arrangement for preventing the jaws from becoming released while the clamp is in use'in a manner to retain the clamp against being accidentally released.

V 2 Fig. 1 is a side elevational view of a clamp constructed in accordance with the present invention.

Fig. 2 is an enlarged fragmentary vertical sec- Fig. '7 is a fragmentary horizontal sectional.

view taken on the line 'I--'I of Fig. 6.

Fig. 8 is a top perspective view of a slide member, per se, used in the form of the invention shown in Figs. 5 to 7.

Fig. 9 is a bottom plan view of the slide member, per se.

Fig. 10 is a side elevational view of the backing piece, per se, .used in the form of the invention shown in Figs. 5 to 9.

Fig. 11 is a top plan view of the backing piec per se.

Fig. 12 is a View similar to Fig. 5, but illustrating the clamp constructed in accordance with a still further modification of the present invention.

'A still further object of the invention proposes slidably mounting the threaded nut in a t'unnellike enlargement which is open along'one side in a manner to facilitate formation of the enlargement and the mounting of the threaded nut therein.

It is a further object of the present inventionto construct a clamp of the type described which is simple and durable and which can be manufactured and sold at a reasonable cost.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended In the accompanying drawings forming a m aterial part or this disclosure:

Ill carried by the mainC-shaped body II having The already mentioned slide member is as a whole marked I2. This member I2 is accommodated in a tunnelled enlargement I4 integral with the clamps main body I I, such tunnel affording a slideway I5 for the member I2. Said member I2 has a fairly large opening I6 therethrough, this opening extending from a rounded endwall I1 of the member I2. The end wall I! has its inner side threaded forming a half-nut I8 facing the opposite plane end wall I9 of the member I2. The wall I9 has a step-down 20.

The step-down or undercut 20 affords a con-.

ventional means for mounting the butt end of a leaf-spring 2I, as by use of a single attaching The spring 2| is a simple leaf- 7 screw 22.

spring, and it has been found that the same should be shaped, for optimum action in normally holding the parts as shown in Fig. 2, that is, for normally maintaining the nut and screw in mesh, substantially as shown in that view.

At 23 is indicated the movable jaw of the clamp, this jaw being roekably and rotatably movable within adequate limits, by inclusion of the conventional ball and socket connection 24. A screw handle 25 is provided at the free end of the screw it) for turning the same.

Means is provided on the member i2 to retain it against accidental sliding movement while the clamp is in use. The retaining, means comprises a shoulder Is see Fig. 2, formed on the rounded end wall l7 and laterally beyond the groove and land elements of the half nut N3, the slide member It incorporates a pair of thin like side walls 26, 28, these merging at their forward ends into the plane end wall it, which wall l9 has an L-extension floor portion 27. In

' lieu of the step-down 23, the member i2 has end wall IQ of the member, opposed to the end wall provided with the spring 2i, for engaging.

the adjacent wall of the enlargement M. The screw Hi has sliding engagement through the walls of the enlargement l4, and when the jaws i i and 2.3 are clamped against the opposite sides of a piece of work 56; as indicated by thedo't and dash lines in Figs. 1 and 2', the screw iii will slide through the enlargement M until the member it engages thertop wall or" the enlarge ment, as shown in'Fi'g. 2. In this position, the shoulder 18 will be engaged with the end of the enlargement id and prevent accidental inward. movement of the member 62 while the clamp is in use. To free the member 32, several turns of the screw it are required moving the member i2 away from the wall of the enlarge inent id until the shoulder se moves clear or the end or" the enlargement after which the member; 2 is free to be urged inward against'zthe action of the spring 2! operation The screw it ordinarily may be spirally ad vanced toward or retracted away fromthe fixed clamp jaw H as usual, by turning the handle 25. When, however, rapid rectilinear and hence non-rotative movement of the jaw 23 is desired, as in the many. cases familiar to those well acquainted with the clamp art, instantaneously this may be temporarily allowed for, merely by thumb thrust against the endof the member 52 at its spring-carrying wall i9, thereby to force the member-J? downward and then inward the slight, distance required to disengage thethreadof the nut fromthe screw. This tensions the spring 2i, so that when said thumb pressure is relieved, immediately the nut snaps back into operative engagement with the hut.

Referring to the modification of the present invention illustrated in Figs. 5--ll, wherein the parts to which are applied reference numerals with primes added correspond, respectively, to'the parts to which have been applied the same reference numerals but without primes, two features are here specially shown. One of these featuresis the use or" exp'ansible coil spring'instead of a leaf spring as in Figs. 1-4, thereby desirably calling for a somewhat difierent structural de sign for the slide member 52''; and the other ofthese features is a slanting of the' slide'way l5, desirably accompanied by a corresponding illclination of the enlargement l t, relative to the of the screw, thereby to obtain a particu-= a step-down 28 which, extended across the top of the wall it and extended partially along the tops of the two walls 2E,"is U-shape'd in top plan. The already mentioned plate or block, to be welded or otherwise suitably attached to the main body of the member 12, to complete the latter, is shown at tt after the already mentioned coil spring is inserted. A lug 353 for centering one end of said spring is carried by the wall [9, and said spring, designated 3|, extends toward a backing piece 32 carrying a spring-endengaging boss 32 As will be noted best from Figs. 10 and 11, the piece 32 has an uninterrupted vertically straight endhor'iz'ontally' coh'cavely curviiinarrace; for fitting against the turns of the land of the screw is, has parallel vertical sides is of a width about equal to the perpendicular spacing between the walls 26,. and has laterally rounded upper and lower ends; all whereby the spring.

35 is always held to ideal action, without chance of entanglement of an end portion thereof with the screw thread.

To guide the slidingmsvements or the backing.

piece 32, the vertical sides thereof have true; nions 32 extending laterally therefrom, which trunnions 32* are 'slidably extended into conipleinentary elongated slots 25 formed inv the side walls 253 of the member l2.

By virtue of the slant of the slideway I5, it has been discovered, the already mentioned optimum ac ion, bothin disengaging and reengaging the screw and nut, is had. In this connection it should be appreciated that while the thread of the screw is shown in all the views in the conventional-manner, that is, for instance, in Fig. 6, as though the said thread side elevationally of the screw has rectilinear upper and lower boundaries; as a matter of fact such-thread at top and bottom would have a sinuous cur vature as thus viewed. In other words, each turn of said thread, at the side of the screw to theleft in Fig. 6 and toward the there remote part or the screw, incorporates a helically extending downward fall-off curvature. Due to this fact, the slant of the slideway l5 in the direction indicated in Fig. 6 is now believed to be preferableand may be proved to be essential,

manual pressure thereon, the'same is' accom panied by a distinct clicking sound and a slight rocking of the member 52 about a horizontal axis intermediate its ends; and this making is allowed for,- as shown in Fig. 6, by putting a slight taper along the top of said member [2".

It is to be understood that the features just described may be employed when a leaf spring is used, as for instance, the leaf spring 21, insteadof such a coil spring as that shown at 3!.

In the further modification of the invention shown in Figs. 12 to 14, the clamp closely resem-- ble' that shown in Figs. 5 to 11. However, in-

this form of the invention, the side of the enlargement M", opposed to the side from which the O-shaped body ll extends is open. This facilitates the formationof the slideway I 5' for the member I2" and further facilitates the engagement of the member I2" in the slideway l5. Also, the member l2" occupies the full space between the top and bottom walls of the enlargement l4" forming the slideway and the member I2" has no shoulder (see 19a in Fig. 6) for restraining the member [2" against accidental movement while the clamp is in use.

In other respects this latter form of the invention is similar to thatshown in Figs. 5 to 11 and similar reference numeralsare used to identifylike parts in each of the several views.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the precise constructions herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in theappended claims.

Having thus described my invention, what I claim as new, and desire to secure by United 20 6. slide being loosely retained in the hollow end piece to permit a limited movement thereof in an axial direction of said clamp screw, tension outerend of the slide so thatit normally is po- 1 means on said slide and' urging said h-alf nut threads laterally into normal engagement with said clamp screw, and a shoulder on said slide engaging said end piece upon a slight axial movement of said slide to prevent-accidental inward movement of said'slide when the clamp is in use.

2. The combination of claim 1 wherein said slide is undercut at a side thereof and said tensionmeans is a leaf spring secured to the undercut of the slide.

3. The combination of .claim 1 wherein said shoulder extends above the upper; surface of the sitioned against the exterior edge of said enlarged end piece.

WILLIAM J. MALECKI.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 150,900 Silveret al May 12, 1874 192,920 Joslyn July 10, 1877 490,603 Schmidt Jan. 24, 1893 807,273 Jirus Dec. 12, 1905 856,436 Walden June 11, 1907 873,859 Hachman Dec. 17, 1907 1,114,415 Thomas Oct. 20, 1914 1,807,080 Woolever May 26, 1931 2,463,263 Gordon Mar. 1, 1949 

